* Two French unions call for farmers to stop delivering milk
* Supported by EU milk union, though no Europe strike call
* Farmers want more EU action to boost depressed milk prices
PARIS, Sept 10 (Reuters) - French dairy producers launched on Thursday a "milk strike", which they hope will spread across Europe and force the authorities to take more action to counter a slump in the dairy sector.
French dairy unions the OPL and APLI called for producers to throw their milk away and not deliver to dairies, after a meeting of the European Milk Board (EMB), a dairy farmers lobby.
"I call for producers to open the floodgates after this evening's milking," said Pascal Massol, APLI's president.
The protesting farmers are hoping the threat of shortages in shops in the coming days will prompt a swift response from the authorities, although the impact of the strike may be limited given that France's main farm union, the FNSEA, opposes it.
The EMB stopped short of calling for a European-wide milk strike, with its president Romuald Schaber saying anti-cartel rules in Germany prevented a similar call there.
But Schaber and representatives from the Netherlands, Belgium, Italy, Switzerland and Luxembourg told the gathering in Paris they would personally participate in the milk strike.
The EMB is notably calling for measures to raise prices paid to farmers to 40 euro cents a litre, compared to lows of around 20 cents this year, to bring prices above production costs.
It also wants the European Union to freeze planned increases in milk quotas, a move opposed by the EU's executive that says it has already taken steps to shore up the dairy sector.
After a price spike in 2007, global dairy markets have deteriorated sharply over the past year, fuelling protests by farmers in France and several other European countries. (Reporting by Gus Trompiz; editing James Jukwey)